1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * This file is part of UBIFS. 4 * 5 * Copyright (C) 2006-2008 Nokia Corporation. 6 * 7 * Authors: Artem Bityutskiy (Битюцкий Артём) 8 * Adrian Hunter 9 */ 10 11 /* This file implements reading and writing the master node */ 12 13 #include "ubifs.h" 14 15 /** 16 * ubifs_compare_master_node - compare two UBIFS master nodes 17 * @c: UBIFS file-system description object 18 * @m1: the first node 19 * @m2: the second node 20 * 21 * This function compares two UBIFS master nodes. Returns 0 if they are equal 22 * and nonzero if not. 23 */ 24 int ubifs_compare_master_node(struct ubifs_info *c, void *m1, void *m2) 25 { 26 int ret; 27 int behind; 28 int hmac_offs = offsetof(struct ubifs_mst_node, hmac); 29 30 /* 31 * Do not compare the common node header since the sequence number and 32 * hence the CRC are different. 33 */ 34 ret = memcmp(m1 + UBIFS_CH_SZ, m2 + UBIFS_CH_SZ, 35 hmac_offs - UBIFS_CH_SZ); 36 if (ret) 37 return ret; 38 39 /* 40 * Do not compare the embedded HMAC aswell which also must be different 41 * due to the different common node header. 42 */ 43 behind = hmac_offs + UBIFS_MAX_HMAC_LEN; 44 45 if (UBIFS_MST_NODE_SZ > behind) 46 return memcmp(m1 + behind, m2 + behind, UBIFS_MST_NODE_SZ - behind); 47 48 return 0; 49 } 50 51 /** 52 * scan_for_master - search the valid master node. 53 * @c: UBIFS file-system description object 54 * 55 * This function scans the master node LEBs and search for the latest master 56 * node. Returns zero in case of success, %-EUCLEAN if there master area is 57 * corrupted and requires recovery, and a negative error code in case of 58 * failure. 59 */ 60 static int scan_for_master(struct ubifs_info *c) 61 { 62 struct ubifs_scan_leb *sleb; 63 struct ubifs_scan_node *snod; 64 int lnum, offs = 0, nodes_cnt, err; 65 66 lnum = UBIFS_MST_LNUM; 67 68 sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1); 69 if (IS_ERR(sleb)) 70 return PTR_ERR(sleb); 71 nodes_cnt = sleb->nodes_cnt; 72 if (nodes_cnt > 0) { 73 snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node, 74 list); 75 if (snod->type != UBIFS_MST_NODE) 76 goto out_dump; 77 memcpy(c->mst_node, snod->node, snod->len); 78 offs = snod->offs; 79 } 80 ubifs_scan_destroy(sleb); 81 82 lnum += 1; 83 84 sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1); 85 if (IS_ERR(sleb)) 86 return PTR_ERR(sleb); 87 if (sleb->nodes_cnt != nodes_cnt) 88 goto out; 89 if (!sleb->nodes_cnt) 90 goto out; 91 snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node, list); 92 if (snod->type != UBIFS_MST_NODE) 93 goto out_dump; 94 if (snod->offs != offs) 95 goto out; 96 if (ubifs_compare_master_node(c, c->mst_node, snod->node)) 97 goto out; 98 99 c->mst_offs = offs; 100 ubifs_scan_destroy(sleb); 101 102 if (!ubifs_authenticated(c)) 103 return 0; 104 105 err = ubifs_node_verify_hmac(c, c->mst_node, 106 sizeof(struct ubifs_mst_node), 107 offsetof(struct ubifs_mst_node, hmac)); 108 if (err) { 109 ubifs_err(c, "Failed to verify master node HMAC"); 110 return -EPERM; 111 } 112 113 return 0; 114 115 out: 116 ubifs_scan_destroy(sleb); 117 return -EUCLEAN; 118 119 out_dump: 120 ubifs_err(c, "unexpected node type %d master LEB %d:%d", 121 snod->type, lnum, snod->offs); 122 ubifs_scan_destroy(sleb); 123 return -EINVAL; 124 } 125 126 /** 127 * validate_master - validate master node. 128 * @c: UBIFS file-system description object 129 * 130 * This function validates data which was read from master node. Returns zero 131 * if the data is all right and %-EINVAL if not. 132 */ 133 static int validate_master(const struct ubifs_info *c) 134 { 135 long long main_sz; 136 int err; 137 138 if (c->max_sqnum >= SQNUM_WATERMARK) { 139 err = 1; 140 goto out; 141 } 142 143 if (c->cmt_no >= c->max_sqnum) { 144 err = 2; 145 goto out; 146 } 147 148 if (c->highest_inum >= INUM_WATERMARK) { 149 err = 3; 150 goto out; 151 } 152 153 if (c->lhead_lnum < UBIFS_LOG_LNUM || 154 c->lhead_lnum >= UBIFS_LOG_LNUM + c->log_lebs || 155 c->lhead_offs < 0 || c->lhead_offs >= c->leb_size || 156 c->lhead_offs & (c->min_io_size - 1)) { 157 err = 4; 158 goto out; 159 } 160 161 if (c->zroot.lnum >= c->leb_cnt || c->zroot.lnum < c->main_first || 162 c->zroot.offs >= c->leb_size || c->zroot.offs & 7) { 163 err = 5; 164 goto out; 165 } 166 167 if (c->zroot.len < c->ranges[UBIFS_IDX_NODE].min_len || 168 c->zroot.len > c->ranges[UBIFS_IDX_NODE].max_len) { 169 err = 6; 170 goto out; 171 } 172 173 if (c->gc_lnum >= c->leb_cnt || c->gc_lnum < c->main_first) { 174 err = 7; 175 goto out; 176 } 177 178 if (c->ihead_lnum >= c->leb_cnt || c->ihead_lnum < c->main_first || 179 c->ihead_offs % c->min_io_size || c->ihead_offs < 0 || 180 c->ihead_offs > c->leb_size || c->ihead_offs & 7) { 181 err = 8; 182 goto out; 183 } 184 185 main_sz = (long long)c->main_lebs * c->leb_size; 186 if (c->bi.old_idx_sz & 7 || c->bi.old_idx_sz >= main_sz) { 187 err = 9; 188 goto out; 189 } 190 191 if (c->lpt_lnum < c->lpt_first || c->lpt_lnum > c->lpt_last || 192 c->lpt_offs < 0 || c->lpt_offs + c->nnode_sz > c->leb_size) { 193 err = 10; 194 goto out; 195 } 196 197 if (c->nhead_lnum < c->lpt_first || c->nhead_lnum > c->lpt_last || 198 c->nhead_offs < 0 || c->nhead_offs % c->min_io_size || 199 c->nhead_offs > c->leb_size) { 200 err = 11; 201 goto out; 202 } 203 204 if (c->ltab_lnum < c->lpt_first || c->ltab_lnum > c->lpt_last || 205 c->ltab_offs < 0 || 206 c->ltab_offs + c->ltab_sz > c->leb_size) { 207 err = 12; 208 goto out; 209 } 210 211 if (c->big_lpt && (c->lsave_lnum < c->lpt_first || 212 c->lsave_lnum > c->lpt_last || c->lsave_offs < 0 || 213 c->lsave_offs + c->lsave_sz > c->leb_size)) { 214 err = 13; 215 goto out; 216 } 217 218 if (c->lscan_lnum < c->main_first || c->lscan_lnum >= c->leb_cnt) { 219 err = 14; 220 goto out; 221 } 222 223 if (c->lst.empty_lebs < 0 || c->lst.empty_lebs > c->main_lebs - 2) { 224 err = 15; 225 goto out; 226 } 227 228 if (c->lst.idx_lebs < 0 || c->lst.idx_lebs > c->main_lebs - 1) { 229 err = 16; 230 goto out; 231 } 232 233 if (c->lst.total_free < 0 || c->lst.total_free > main_sz || 234 c->lst.total_free & 7) { 235 err = 17; 236 goto out; 237 } 238 239 if (c->lst.total_dirty < 0 || (c->lst.total_dirty & 7)) { 240 err = 18; 241 goto out; 242 } 243 244 if (c->lst.total_used < 0 || (c->lst.total_used & 7)) { 245 err = 19; 246 goto out; 247 } 248 249 if (c->lst.total_free + c->lst.total_dirty + 250 c->lst.total_used > main_sz) { 251 err = 20; 252 goto out; 253 } 254 255 if (c->lst.total_dead + c->lst.total_dark + 256 c->lst.total_used + c->bi.old_idx_sz > main_sz) { 257 err = 21; 258 goto out; 259 } 260 261 if (c->lst.total_dead < 0 || 262 c->lst.total_dead > c->lst.total_free + c->lst.total_dirty || 263 c->lst.total_dead & 7) { 264 err = 22; 265 goto out; 266 } 267 268 if (c->lst.total_dark < 0 || 269 c->lst.total_dark > c->lst.total_free + c->lst.total_dirty || 270 c->lst.total_dark & 7) { 271 err = 23; 272 goto out; 273 } 274 275 return 0; 276 277 out: 278 ubifs_err(c, "bad master node at offset %d error %d", c->mst_offs, err); 279 ubifs_dump_node(c, c->mst_node); 280 return -EINVAL; 281 } 282 283 /** 284 * ubifs_read_master - read master node. 285 * @c: UBIFS file-system description object 286 * 287 * This function finds and reads the master node during file-system mount. If 288 * the flash is empty, it creates default master node as well. Returns zero in 289 * case of success and a negative error code in case of failure. 290 */ 291 int ubifs_read_master(struct ubifs_info *c) 292 { 293 int err, old_leb_cnt; 294 295 c->mst_node = kzalloc(c->mst_node_alsz, GFP_KERNEL); 296 if (!c->mst_node) 297 return -ENOMEM; 298 299 err = scan_for_master(c); 300 if (err) { 301 if (err == -EUCLEAN) 302 err = ubifs_recover_master_node(c); 303 if (err) 304 /* 305 * Note, we do not free 'c->mst_node' here because the 306 * unmount routine will take care of this. 307 */ 308 return err; 309 } 310 311 /* Make sure that the recovery flag is clear */ 312 c->mst_node->flags &= cpu_to_le32(~UBIFS_MST_RCVRY); 313 314 c->max_sqnum = le64_to_cpu(c->mst_node->ch.sqnum); 315 c->highest_inum = le64_to_cpu(c->mst_node->highest_inum); 316 c->cmt_no = le64_to_cpu(c->mst_node->cmt_no); 317 c->zroot.lnum = le32_to_cpu(c->mst_node->root_lnum); 318 c->zroot.offs = le32_to_cpu(c->mst_node->root_offs); 319 c->zroot.len = le32_to_cpu(c->mst_node->root_len); 320 c->lhead_lnum = le32_to_cpu(c->mst_node->log_lnum); 321 c->gc_lnum = le32_to_cpu(c->mst_node->gc_lnum); 322 c->ihead_lnum = le32_to_cpu(c->mst_node->ihead_lnum); 323 c->ihead_offs = le32_to_cpu(c->mst_node->ihead_offs); 324 c->bi.old_idx_sz = le64_to_cpu(c->mst_node->index_size); 325 c->lpt_lnum = le32_to_cpu(c->mst_node->lpt_lnum); 326 c->lpt_offs = le32_to_cpu(c->mst_node->lpt_offs); 327 c->nhead_lnum = le32_to_cpu(c->mst_node->nhead_lnum); 328 c->nhead_offs = le32_to_cpu(c->mst_node->nhead_offs); 329 c->ltab_lnum = le32_to_cpu(c->mst_node->ltab_lnum); 330 c->ltab_offs = le32_to_cpu(c->mst_node->ltab_offs); 331 c->lsave_lnum = le32_to_cpu(c->mst_node->lsave_lnum); 332 c->lsave_offs = le32_to_cpu(c->mst_node->lsave_offs); 333 c->lscan_lnum = le32_to_cpu(c->mst_node->lscan_lnum); 334 c->lst.empty_lebs = le32_to_cpu(c->mst_node->empty_lebs); 335 c->lst.idx_lebs = le32_to_cpu(c->mst_node->idx_lebs); 336 old_leb_cnt = le32_to_cpu(c->mst_node->leb_cnt); 337 c->lst.total_free = le64_to_cpu(c->mst_node->total_free); 338 c->lst.total_dirty = le64_to_cpu(c->mst_node->total_dirty); 339 c->lst.total_used = le64_to_cpu(c->mst_node->total_used); 340 c->lst.total_dead = le64_to_cpu(c->mst_node->total_dead); 341 c->lst.total_dark = le64_to_cpu(c->mst_node->total_dark); 342 343 ubifs_copy_hash(c, c->mst_node->hash_root_idx, c->zroot.hash); 344 345 c->calc_idx_sz = c->bi.old_idx_sz; 346 347 if (c->mst_node->flags & cpu_to_le32(UBIFS_MST_NO_ORPHS)) 348 c->no_orphs = 1; 349 350 if (old_leb_cnt != c->leb_cnt) { 351 /* The file system has been resized */ 352 int growth = c->leb_cnt - old_leb_cnt; 353 354 if (c->leb_cnt < old_leb_cnt || 355 c->leb_cnt < UBIFS_MIN_LEB_CNT) { 356 ubifs_err(c, "bad leb_cnt on master node"); 357 ubifs_dump_node(c, c->mst_node); 358 return -EINVAL; 359 } 360 361 dbg_mnt("Auto resizing (master) from %d LEBs to %d LEBs", 362 old_leb_cnt, c->leb_cnt); 363 c->lst.empty_lebs += growth; 364 c->lst.total_free += growth * (long long)c->leb_size; 365 c->lst.total_dark += growth * (long long)c->dark_wm; 366 367 /* 368 * Reflect changes back onto the master node. N.B. the master 369 * node gets written immediately whenever mounting (or 370 * remounting) in read-write mode, so we do not need to write it 371 * here. 372 */ 373 c->mst_node->leb_cnt = cpu_to_le32(c->leb_cnt); 374 c->mst_node->empty_lebs = cpu_to_le32(c->lst.empty_lebs); 375 c->mst_node->total_free = cpu_to_le64(c->lst.total_free); 376 c->mst_node->total_dark = cpu_to_le64(c->lst.total_dark); 377 } 378 379 err = validate_master(c); 380 if (err) 381 return err; 382 383 err = dbg_old_index_check_init(c, &c->zroot); 384 385 return err; 386 } 387 388 /** 389 * ubifs_write_master - write master node. 390 * @c: UBIFS file-system description object 391 * 392 * This function writes the master node. Returns zero in case of success and a 393 * negative error code in case of failure. The master node is written twice to 394 * enable recovery. 395 */ 396 int ubifs_write_master(struct ubifs_info *c) 397 { 398 int err, lnum, offs, len; 399 400 ubifs_assert(c, !c->ro_media && !c->ro_mount); 401 if (c->ro_error) 402 return -EROFS; 403 404 lnum = UBIFS_MST_LNUM; 405 offs = c->mst_offs + c->mst_node_alsz; 406 len = UBIFS_MST_NODE_SZ; 407 408 if (offs + UBIFS_MST_NODE_SZ > c->leb_size) { 409 err = ubifs_leb_unmap(c, lnum); 410 if (err) 411 return err; 412 offs = 0; 413 } 414 415 c->mst_offs = offs; 416 c->mst_node->highest_inum = cpu_to_le64(c->highest_inum); 417 418 ubifs_copy_hash(c, c->zroot.hash, c->mst_node->hash_root_idx); 419 err = ubifs_write_node_hmac(c, c->mst_node, len, lnum, offs, 420 offsetof(struct ubifs_mst_node, hmac)); 421 if (err) 422 return err; 423 424 lnum += 1; 425 426 if (offs == 0) { 427 err = ubifs_leb_unmap(c, lnum); 428 if (err) 429 return err; 430 } 431 err = ubifs_write_node_hmac(c, c->mst_node, len, lnum, offs, 432 offsetof(struct ubifs_mst_node, hmac)); 433 434 return err; 435 } 436